Flow Investigations in the Crossover System of a Centrifugal Compressor Stage

Reddy, K. Srinivasa,Murty, G.V. Ramana,Dasgupta, A.,Sharma, K.V. Korean Society for Fluid machinery 2010 International journal of fluid machinery and syste Vol.3 No.1

The performance of the crossover system of a centrifugal compressor stage consisting of static components of $180^{\circ}$ U-bend, return channel vanes and exit ducting with a $90^{\circ}$ bend is investigated. This study is confined to the assessment of performance of the crossover system by varying the shape of the return channel vanes. For this purpose two different types of Return Channel Vanes (RCV1 and RCV2) were experimentally investigated. The performance of the crossover system is discussed in terms of total pressure loss coefficient, static pressure recovery coefficient and vane surface pressure distribution. The experimentation was carried out on a test setup in which static swirl vanes were used to simulate the flow at the exit of an actual centrifugal compressor impeller with a design flow coefficient of 0.053. The swirl vanes are connected to a mechanism with which the flow angle at the inlet of U-bend could be altered. The measurements were taken at five different operating conditions varying from 70% to 120% of design flow rate. On an overall assessment RCV1 is found to give better performance in comparison to RCV2 for different U-bend inlet flow angles. The performance of RCV2 was verified using numerical studies with the help of a CFD Code. Three dimensional sector models were used for simulating the flow through the crossover system. The turbulence was predicted with standard k-$\varepsilon$, 2-equation model. The iso-Mach contour plots on different planes and development of secondary flows were visualized through this study.

Investigation on the local electronic/atomic structure properties using XANES/EXAFS and photocatalyst application of Zr_1-xCu_xO₂ (0 @? x @? 0.2)

Sharma, A.,Varshney, M.,Chae, K.H.,Shin, H.J.,Won, S.O. Elsevier 2016 Current Applied Physics Vol.16 No.10

<P>We investigated local electronic/atomic structure properties by using X-ray absorption spectroscopy and demonstrated the photocatalyst application of Zr1-xCuxO2 (0 <= x <= 0.2) samples. X ray diffraction (XRD) results revealed the amorphous nature of the samples; however, transmission electron microscopy (TEM) depicted the formation of < 2 nm sized particles in all of the samples. Local electronic structure was investigated by X-ray absorption near edge structure (XANES) at O K-edge, Zr K-edge and Cu K-edge. The O K-edge XANES suggested strong hybridization of s-p-d orbitals upon Cu doping. The Cu K-edge XANES confirmed +1 valence state of Cu (Cu+1) in all of the Cu doped ZrO2 samples. Extended X-ray absorption fine structure (EXAFS) analysis at the Zr K-edge nullifies the formation of trivial phases and confirms the local monoclinic structure in all of the samples. Photocatalyst properties of the samples were investigated by monitoring the net degradation in the methyl orange dye aqueous solution under the UV light irradiation. The Cu doped ZrO2 samples exhibited superior photo-catalyst properties over the undoped ZrO2. (C) 2016 Elsevier B.V. All rights reserved.</P>

X-ray absorption spectroscopy study and photocatalyst application of CuO and Cu_0.9Ti_0.1O nanoparticles

Sharma, A.,Varshney, M.,Ha, T.K.,Chae, K.H.,Shin, H.J. Elsevier 2015 Current Applied Physics Vol.15 No.10

We report detailed investigations on the electronic structure and photocatalyst application of CuO and Cu<SUB>0.9</SUB>Ti<SUB>0.1</SUB>O nanoparticles (NPs). The NPs were prepared by co-precipitation method and subsequent annealing. Crystal structure and morphology of the NPs were investigated by synchrotron X-ray diffraction and high resolution transmission electron microscope, respectively. The local atomic structure around the Cu atoms was investigated by the extended X-ray absorption fine structure (EXAFS) at the Cu K-edge. Electronic structure determination was done using near edge X-ray absorption fine structure (NEXAFS) at the O K-edge, Cu L-edge, Cu K-edge and Ti L-edge. From the structural and electronic structure investigations, it is inferred that the Ti substitutes the Cu in CuO lattice without forming any secondary phases and the valence state of Cu is not affected by the Ti substitution; however the Cu - O bond length is found to be shorten in the Ti doped sample. As prepared NPs exhibit excellent photocatalyst application toward the degradation of methyl orange (MO) and potassium dichromate (PD) pollutant dyes under the visible light irradiation. The mechanism of the photodegradation of MO and PD pollutants, by the smaller sized CuO and larger sized Cu<SUB>0.9</SUB>Ti<SUB>0.1</SUB>O NPs, is briefly discussed.

X-ray absorption spectroscopy investigations on electronic structure and luminescence properties of Eu:SnO₂-SnO nanocomposites

Sharma, A.,Varshney, M.,Shin, H.J.,Chae, K.H.,Won, S.O. Elsevier 2016 CURRENT APPLIED PHYSICS Vol.16 No.10

<P>Tin oxide nanostructures are nontoxic in nature and biocompatible. However, they exhibit weak emission characteristics that limit their applications in cellular and biology fields. Therefore, it is important to enhance luminescence properties in this oxide and establish a relationship between the local electronic structure and emission characteristics. In this report, we demonstrate significant advancement in the photoluminescence (PL) properties in the Eu incorporated SnO2-SnO nanocomposites. Eu: SnO2-SnO nanocomposites were synthesized by chemical precipitation method. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and PL measurements were performed to investigate the structural, electronic structure and emission properties of the samples. Eu3+ ions, as confirmed by the Eu M-5,M-4-edge XANES studies, lead to defect formation and local electronic structural perturbation in the nanocomposites. The O K-edge and Sn M-5,M-4-edge XANES studies confirm a net decrease in the hybridization of O 2p and Sn 5s/5p states and formation of Sn defects, upon Eu doping. Significant enhancement in the Eu3+ related interband transitions (D-5(0)-F-7(J); J = 0,1,2,3,4) is achieved upon increasing the Eu concentrations, indicating synthesis of emission characteristic rich SnO2-SnO nanocomposites. (C) 2016 Elsevier B.V. All rights reserved.</P>

Solution processed bulk heterojunction solar cells based on A-D-A small molecules with a dihydroindoloindole (DINI) central donor and different acceptor end groups

Sim, J.,Lee, H.,Song, K.,Biswas, S.,Sharma, A.,Sharma, G.,Ko, J. Royal Society of Chemistry 2016 Journal of Materials Chemistry C Vol.4 No.16

<P>Four acceptor-donor-acceptor (A-D-A) small molecules with dihydroindoloindole (DINI) as the central donor unit and different acceptor end groups such as dicyanovinylene (DCV), indenedione (IND), cyanoacrylate (CA) and rhodanine (Rho) linked through bithiophene as the p-linker, DINI-DCV, DINI-IND, DINI-CA and DINI-Rho, were designed and synthesized for the application as donor materials along with PC71BM as an acceptor for solution processed organic bulk heterojunction solar cells. The effect of acceptor end groups on the photovoltaic performance was investigated. The organic solar cells (OSCs) based on as cast DINI-IND showed the highest power conversion efficiency of 3.04%, as cast DINI-CA showed the lowest PCE of 1.63% and the other two exhibit a PCE in between them. These results showed that acceptor end groups affect the overall performance of the cells. The PCE of OSCs has been further improved up to 7.04% and 6.16% employing two-step annealing (TSA) treated DIN-IND: PC71BM (1 : 2) and DIN-CN : PC71BM (1 : 2), respectively. The enhancement in the PCE of OSCs with TSA treated active layers is attributed to the better nanophase morphology, the increase in the crystalline nature and light harvesting efficiency and more balanced charge transport and charge collection probability.</P>

Influence of Ni doping on PtNi nanoparticles: Synthesis, electronic/atomic structure and photocatalyst investigations

Varshney, M.,Sharma, A.,Shin, H.J.,Lee, H.H.,Jeon, T.Y.,Lee, B.H.,Chae, K.H.,Won, S.O. Pergamon Press 2017 The Journal of physics and chemistry of solids Vol.110 No.-

Carbon-supported Pt and PtNi nanoparticles (NPs) were synthesized using a borohydride reduction method. Structural properties were studied by synchrotron X-ray diffraction (XRD) and the size/shape of the NPs was determined by transmission electron microscope (TEM). X-ray absorption spectroscopy with its two amendments; X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), has been employed to investigate the local electronic/atomic structure surrounding the Pt and Ni atoms. XANES results, at Pt L<SUB>3</SUB>-edge and Ni K-edge, have shown fractional oxidation of Pt and Ni atoms. The Pt3Ni1NPs have exhibited a lower bond distance of Pt-Ni shell and higher coordination number of Pt-Ni shells, indicating the alloy formation between Pt and Ni. We further have demonstrated that the Pt and PtNi NPs can serve as effective photocatalysts towards the degradation of water pollutant dye (methyl orange (MO)). By considering the interband charge-transfer of Pt (5d →6sp), a tentative mechanism is proposed to understand the photocatalytic degradation of MO dye molecules by Pt/PtNi NPs under the light irradiation.

Genotype by Dietary Lysine Interaction for Growth and Response to Sheep Red Blood Cells and Escherichia coli Inoculation in Commercial Broiler Chicks

Praharaj, N.K.,Reddy, M.R.,Panda, A.K.,Rama Rao, S.V.,Sharma, R.P. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.8

An experiment was conducted to assess the interaction between genotypes and dietary lysine content in commercial broiler chicks by measuring growth, and response to sheep red blood cells (SRBC) and Escherichia coli (E.coli) inoculation. Female chicks from four genotypes (A=Anak 2000; B=Hubbard; C=Cobb and D=Synthetic broiler) were fed four levels of lysine in diet from d old till the end of experiment. The lysine content of the diet was 9.61, 10.51, 11.41 and 12.31 g/kg. Body weights at 0, 14, 28 and 42 d of age and pen-wise feed intake till 14, 28 and 42 d of age were recorded. Production of antibody against SRBC and resistance to E.coli were measured at 5 d of post inoculation (PI) at 43 d of age. Also, response to phytohemaglutinin-P (PHA-P) was measured at 12 and 24 h of PI at 48 d of age. Genotype by dietary lysine interaction was significant for body weights at 14 and 28 d of age, but not at 42 d of age. Genotype by dietary lysine interaction was not significant for feed efficiency, for antibody titers against SRBC, and for air sac lesion score, relative bodyweight change, and relative weights of bursa and spleen in response to E.coli inoculation. However, a significant interaction was observed between the levels of lysine and dosage of SRBC for antibody titers. There was significant genotype by dietary lysine interaction for cutaneous basophilic hypersensitivity (CBH) response to PHA-P at 12 and 24 h of PI. It may be concluded that to obtain optimum body weight and immunity in commercial broilers the dietary lysine requirement may be recommended specific to the genotype.

Rapid thermal annealing induced modification in structural and electronic structure properties of Ti_0.95Co_0.05O_2@?δ thin films

Rodrigues, E.C.,Sharma, S.K.,de Menezes, A.S.,Chae, K.H.,Gautam, S.,Aljawf, R.N.,Kumar, S. Pergamon Press 2016 Materials research bulletin Vol.83 No.-

Thin film of Ti<SUB>0.95</SUB>Co<SUB>0.05</SUB>O<SUB>2-δ</SUB> was deposited on Si (100) using PLD method and annealed in O<SUB>2</SUB> and N<SUB>2</SUB> environment. Raman spectra confirm that all the films have rutile structure. Surface morphology indicates that the surface roughness and grain size increase with annealing. The electronic structure studied by NEXAFS spectroscopy at O K, Ti L<SUB>3,2</SUB> and Co L<SUB>3,2</SUB>-edges revealed that peak intensities decrease significantly for the film annealed N<SUB>2</SUB> environment. The ligand-field splitting estimated from the energy difference between the t<SUB>2g</SUB> and e<SUB>g</SUB> features in O K-edge spectra were 2.71eV for as-deposited and O<SUB>2</SUB> annealed film, whereas reduced more than double (@?1.32eV) for the film annealed in N<SUB>2</SUB>. Atomic multiplet calculations and experimentally observed NEXAFS spectra at Co L<SUB>3,2</SUB>-edge and Ti L<SUB>3,2</SUB>-edge confirm that Co present in 2+ and Ti in +4 valence state, whereas the multiplet structures of O<SUB>2</SUB> annealed film looks similar to Co metal.

Anti-Allergic Effects of Herbal Product from Allium cepa (Bulb)

P. Kaiser,M.S. Youssouf,S.A. Tasduq,S. Singh,S.C. Sharma,G.D. Singh,V.K. Gupta,B.D. Gupta,R.K. Johri 한국식품영양과학회 2009 Journal of medicinal food Vol.12 No.2

Allium cepa (Family Liliaceae) is a reputed Indian medicinal herb that is prescribed as an effective remedy for several ailments in the Ayurvedic system of medicine. The aim of this study was to evaluate its efficacy against various events responsible for Type I allergic reactions. A herbal fraction (ALC-02) from A. cepa (bulb) inhibited histamine release and attenuated intracellular calcium levels in Compound 48/80-induced rat peritoneal mast cells. It also prevented Compound 48/80-mediated systemic anaphylaxis while lowering histamine levels in plasma. ALC-02 suppressed carrageenan-induced rat paw edema. It inhibited eosinophil peroxidase activity and protein content in bronchoalveolar lavage fluid (BALF) of ovalbumin-challenged mice. In this experiment ALC-02 also caused a substantial reduction in lipid peroxidation in BALF/lung tissue and augmented superoxide dismutase activity in lung tissue. ALC-02 suppressed erythrocytic lysis caused by Triton X-100. A significant quenching of 1,1-diphenyl-2-picrylhydrazyl radical by ALC-02 was observed. The results have shown a promising anti-allergic profile of ALC-02 that could be attributed to its potential antihistaminic, anti-inflammatory, and antioxidant activities.

Anti-Allergic Effects of Herbal Product from Allium cepa (Bulb)

Kaiser, P.,Youssouf, M.S.,Tasduq, S.A.,Singh, S.,Sharma, S.C.,Singh, G.D.,Gupta, V.K.,Gupta, B.D.,Johri, R.K. The Korean Society of Food Science and Nutrition 2009 Journal of medicinal food Vol.12 No.2

Allium cepa (Family Liliaceae) is a reputed Indian medicinal herb that is prescribed as an effective remedy for several ailments in the Ayurvedic system of medicine. The aim of this study was to evaluate its efficacy against various events responsible for Type I allergic reactions. A herbal fraction (ALC-02) from A. cepa (bulb) inhibited histamine release and attenuated intracellular calcium levels in Compound 48/80-induced rat peritoneal mast cells. It also prevented Compound 48/80-mediated systemic anaphylaxis while lowering histamine levels in plasma. ALC-02 suppressed carrageenan-induced rat paw edema. It inhibited eosinophil peroxidase activity and protein content in broncho alveolar lavage fluid (BALF) of ovalbumin-challenged mice. In this experiment ALC-02 also caused a substantial reduction in lipid peroxidation in BALF/lung tissue and augmented superoxide dismutase activity in lung tissue. ALC-02 suppressed erythrocytic lysis caused by Triton X-100. A significant quenching of 1,1-diphenyl-2-picrylhydrazyl radical by ALC-02 was observed. The results have shown a promising anti-allergic profile of ALC-02 that could be attributed to its potential antihistaminic, anti-inflammatory, and antioxidant activities.